Apparatus for crushing rocks and other materials are well known. Many crushing apparatus incorporate a stationary jaw and a swing jaw which move towards and away from each other during use to crush rocks therebetween. The swing jaw may be straight, as in the well known "Blake" type crushers (cf. GB-853080), or cantilevered as in the crusher disclosed in GB-2232095, for example.
The manner in which the various types of crushing apparatus function varies considerably depending upon whether the swing jaw is straight or cantilevered. The present invention relates solely to the cantilevered type swing jaw crushing apparatus.
WO 89/04718 (GB-2232095) discloses a cantilevered swing jaw crushing apparatus comprising a main frame, a stationary law, a cantilevered swing jaw mounted about a top pivot axis and means for driving the swing jaw. The apparatus further includes a vertical impact plate mounted on the main frame for protecting the swing jaw from rocks entering the crushing apparatus through the feed opening. The rocks strike the impact plate which absorbs the energy associated therewith. Although such an impact plate is useful in a crushing apparatus, because it reduces the forces applied to the mounting hinge of the swing jaw, the arrangement is not ideal and the present invention aims to improve upon it.